Automated drill bit changer

ABSTRACT

A drill bit changer system for a drill rig includes a drill bit storage holder rotatably and pivotally mounted to the drill rig and a plurality of bit holder assemblies located within the drill bit storage holder. Each bit holder assembly includes a receptacle, wherein the plurality of bit holder assemblies are arranged to receive a drill bit in each receptacle. The drill bit storage holder is pivotally connected between a stowed position and an engaged position in which the drill bit is positioned at a drill string of the drill rig, wherein the drill bit storage holder is further indexable to present a respective receptacle at the drill string such that the drill bit is added or removed from the drill string. A method of changing a drill bit is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/949,870 filed Apr. 10, 2018, which claims priority of U.S.Provisional Application No. 62/483,808, filed Apr. 1, 2015, which theentirety thereof is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to an automated drill bit changing systemfor a mobile drill rig and a bit changing process.

BACKGROUND

Mobile drill rigs are commonly used in surface mining operations.Surface mining requires drilling patterns of holes to specific depthsand angles into the drill bed. Self-propelled rigs preliminarily drillthese holes. Later, the mine uses sequences of explosive charges tobreak up the bedrock (or other subsurface constituents) so that thelarge end loaders or drag lines can scoop up the material to transfer todump trucks for relocation to the processing areas at the mine.

Many of the operations involved in servicing and maintaining the rigsare difficult and hazardous. Finding ways to automate these processescan, not only result in a machine that is easier to maintain, but alsoreduce cost and increase efficiency. One such task is replacing therotary drill bit.

The current process for changing out bits is done manually with amechanic and an operator. However, the leading standard today in drillrig technology is automation. Customers and suppliers would like toreduce the need for operators of the drill rig to increase safety andefficiency. Many tasks performed by the above type of drill rig havebeen successfully automated, however, automation of changing a drill bithas been attempted but has proven difficult to perfect.

Automating the process is needed in order to keep moving forward withthe growing needs of the industry. By using the process of automationbit replacement, time can be drastically reduced and a faster, morereliable mechanism to change bits ultimately will save money. It willalso improve the safety and eliminate potential bodily harm to themechanic and/or the operator by eliminating the need for humaninteraction with the heavy drill bits and the confined operatingenvironment.

One hindering factor towards automating bit changing is that rig spaceis limited, meaning that the machine will have to be engineered to fiton a variety of rigs without using too much space.

Another problem of automated drill bit changing is the non-uniformgeometry of the drill bit itself. When the bit rotates, a differentsurface is presented, making it difficult to have a form fitted deviceto grab onto the bit. The carbide steel that the bit is made out of alsocauses damage to softer metals being used to grab the bit.

Thus, there is a need for an automated blast drill bit changing systemthat is capable of being automated, reliable, capable of being easilyfitted to a blast-hole drill rig, designed to allow for easy restockingof bits, capable of storing new bits and holding the old bits afterbeing replaced, robust, compact and able to handle extreme conditions,and safe to use.

SUMMARY

The aim of the present disclosure is to overcome or at least reduce theabove-mentioned problems. Therefore, the present disclosure relates to adrill bit changer system for a drill rig, the system including a drillbit storage holder rotatably and pivotally mounted to the drill rig, anda plurality of bit holder assemblies located within the drill bitstorage holder, each bit holder assembly including a receptacle, whereinthe plurality of bit holder assemblies are arranged to receive a drillbit in each receptacle, the drill bit storage holder being pivotallyconnected between a stowed position and an engaged position in which thedrill bit is positioned at a drill string of the drill rig, wherein thedrill bit storage holder is further indexable to present a respectivereceptacle at the drill string such that the drill bit is added orremoved from the drill string.

A method of changing a drill bit of a drill rig includes the steps ofproviding a method of changing a drill bit of a drill rig includes thesteps of providing a drill bit changer system, the drill bit changersystem including a drill bit storage holder rotatably and pivotallymounted to the drill rig, and a plurality of bit holder assemblieslocated within the drill bit storage holder, each bit holder assemblyincluding a receptacle, wherein the plurality of bit holder assembliesare arranged to receive a drill bit in each receptacle; pivoting thedrill bit storage holder to a first position whereby the drill bitstorage holder is positioned to engage a drill string of the drill rig;removing a used drill bit and adaptor assembly from the drill string;indexing the drill bit storage holder to position a new drill bit to thedrill string; attaching the new drill bit adaptor assembly to the drillstring; and pivoting the drill bit storage system to a second positionwhereby the drill bit storage system is stowed away from the drillstring.

By using available technology, such as sensors, hydraulics,electromagnets, and motors, it is possible to revolutionize the processfor changing mining bits.

The foregoing summary, as well as the following detailed description ofthe embodiments, will be better understood when read in conjunction withthe appended drawings. It should be understood that the embodimentsdepicted are not limited to the precise arrangements andinstrumentalities shown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic view of a mobile drill rig with an automated drillbit changing system according to the present disclosure.

FIG. 2 is a perspective view of the drill bit changing system.

FIG. 3 is an enlarged perspective view of the drill bit storage holderof the present disclosure.

FIG. 4 is an enlarged perspective view of the drill bit and adaptorassembly.

FIG. 5 is a schematic view of the automated control system of thepresent disclosure.

FIGS. 6A-6E illustrate the drill bit changing process according to thesystem of the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to a drill bit changing system forremoving worn out bits from a drill string and replacing such with newbits with limited need for physical human intervention, i.e., a machineoperator and/or maintenance personnel. Referring to FIG. 1, a movableblast hole rig 10 includes a mast or derrick 12. It should beappreciated that although the system of the present disclosure isdescribed in relation to a drill rig, the same can be used on differenttypes of apparatus. An automated drill bit changer 20, which will bedescribed in detail below, is movably disposed on the mast.

At least one control unit 16 is arranged to control various componentsof the drill bit changer 20. The control unit 16 can be a computer,processing device, or any corresponding device arranged to execute acomputer executable code and may include a user interface with a displaydevice as well as control means for giving commands and information tothe drill bit changer 20. Control unit 16 may be a computer equippedwith appropriate software that can be accessed and controlled by theoperator of the drill rig. Additionally, control unit can be operatedremotely. By using sensors, hydraulics, electromagnets, and motors, itis possible to automate the process for changing mining bits.

Some details of the selected hardware of drill bit changer 20 that willperform the necessary functions are described with reference to FIGS.2-6E. The objectives of each of the hardware components are derived fromthe critical sub functions that each performs, for example, holding andstoring of the adaptors and an adaptor/bit assembly, as will bedescribed further herein. Each of these subsystems has its own uniquemechanisms to accomplish the objectives.

Referring to FIGS. 2 and 3, a first component of the drill bit changer20 is a bit storage holder 22 for bits 24. The bit storage holder 22 caninclude a carousel 26 having a plurality of bit receptacles 28 forreceiving the bits 24 and adaptor 30 that together form the drill bitadaptor assembly. It should be appreciated that although shown as a cuptype receptacle, other bit holder arrangements are contemplated.

Carousel 26 is movably positioned on mast 12 via pivoting arm assemblies32 and mast mounts 34. Each arm assembly includes a hydraulic cylinder36 that can be controlled by control unit 16 as described furtherherein.

The bit storage holder 22 keeps the bit/adaptor in place so that it canbe correctly positioned to be able to add/remove it to/from the drillstring. It also provides storage for used and unused adaptor/bitassemblies. The bit storage holder 22 also includes a top 27, whichkeeps the drill bit adaptor assemblies 24, 30 in place when themast/derrick of the rig is lowered to horizontal position and trammed.The drill bit storage holder 22 is mounted to the arm assemblies 32 viaa central shaft 33 that connects the two mounting arms.

Bit storage holder 22 is arranged to hold a plurality of bits, forexample, between 3-6 bits. However, due to space constraints, the bitstorage system should not have a size that would interfere with thecurrent drill tower due to rotation of the bit holder 22. Drill bitstorage holder 22 is arranged to be able to rotate and index to a properposition so the drill pipe can connect with a new bit. Accordingly, thedrill bit storage holder is indexed by a slew drive 38. Slew drive 38can be a worm gear mechanism actuated by a hydraulic motor capable ofprovide rotational actuation. Indexing of the slew drive can becontrolled by control unit 16.

As will be described further herein, the slew drive indexes the carouselfrom one bit receptacle 28 to the next to allow the drill bit adaptorassemblies 24, 30 to be accessed. An encoder 37 is mounted to centralshaft 33 to monitor the position of the new/used bits so that theprocess is automated through control system 16.

The bit storage holder 22 must be able to support the load of all ofbits and the bit adaptors. Thus, the material thereof is chosen so as tobe strong enough and to prevent deflection of the bit storage that maylead to alignment issues.

Referring to FIG. 4, and as set forth above, a plurality of drill bitadaptor 30 and drill bits 24 are accommodated in drill bit storageholder 22. Adaptor 30 aides in the automation process as it is easier toremove and add the bit adaptor to the drill string than the bit. The bitadaptor 30 can be a tube having a pin thread on one end 42 to engagewith the drill string under the rotary head and another having a threadon an opposed end 44 to engage with a bit 24. Typically on blast holerigs API or beco threads are used. Additionally, the bit adaptor has anecked down, section 46, which is engaged by adaptor arm 40 to hold theadaptor/bit assembly so that the threaded joint between the adaptor andthe drill string can be broken and a new adaptor/bit assembly can beadded to the drill string.

Because bits are by nature not uniformly shaped and are not easilyhandled with mechanisms, adaptor 30 can be more easily handled bycurrently used mechanisms. Additionally, drill pipes, adapters and toolscan be equipped with flats cut into the wall to hold and arrest therotation and enable the breaking of the threaded joints between parts toadd/remove pieces. However, these flats can be difficult to adapt toautomation as they have to be aligned. The interface of adaptor 30 atsection 46 can be more easily automated.

FIG. 5 illustrates the automated control system including control unit16. As shown, control unit 16 communicates with slew drive 38, hydraulicarm assemblies 32 and encoder 37. As set forth supra, the drill bitstorage holder 22 is indexed by slew drive 38 to provide rotationalactuation. Indexing of the slew drive can be controlled by control unit16. Each of the arm assembly hydraulic cylinders 36 can also becontrolled by control unit 16 to pivot the holder 22 into and out ofposition. Moreover, encoder 37 is mounted to central shaft 33 to monitorthe position of the bits to enable automated control by unit 16.

FIGS. 6A-6Ee illustrate the drill bit changing process. In the firststep shown in FIG. 6A, drill pipe finishes drilling and raises up. Instep 2, FIG. 6B, drill bit storage holder 22 is rotated to meet the pipeand empty arm 40 engages the section of adaptor 30, the bit adaptorbeing previously broken loose from the bit sub by a deck wrench (notshown) as the bit storage holder moves into place. With the top 27removed for illustration, next as shown in FIG. 6C, the uses bit andadaptor assembly held by arm 40 is unscrewed by manipulating the drillrigs feeding and rotation system. Next as shown in FIG. 6D, drill bitstorage holder 22 is controlled to be indexed by slew drive 38 toposition a new bit and adaptor to the pipe and the same is screwed ontothe drill pipe as disclosed above, but in an opposite direction ofrotation of the rig feeding and rotation system. In the last step, FIG.6E, the assembly swings back out of the way and drilling commences.

As set forth supra, the mounting arms are mounted to the mast/derrickvia mast mounts and actuated by hydraulic cylinders. The actuatedcylinders move the holding/storage mechanism from a stowed position(FIG. 6a ) to an engaged swung in position (FIG. 6B) for a new/usedadaptor bit assembly to be added/removed. It should be appreciated thatthe drill bit storage holder mechanism must be able to move out of theway during regular drilling operations. It moves out of the way via thesame hydraulic cylinders that swing the holding/storage mechanism intoposition to add/remove the adaptor/bit sub. The system is alsoresponsible for moving the bit storage into the proper position so thatit can then index to its proper position. The carousel 26 holds all ofthe individual bits for storage. The carousel is able to rotate due tothe slew drive shown underneath the bit storage area.

The present drill bit changing system externally interacts with theoperator, the environment and the drill rig itself. A robust,weatherproof design is required to withstand environmental abuse. Thedrill rig will be applying numerous forces to the bit changing system,so a robust attachment at the joint will be required.

The drill rigs operate in very harsh environments. The rigs are designedto withstand extreme temperatures, rain and snow and debris damage. Thedrill bit changing system proposed here will need to withstand thesesame conditions. These conditions can damage and ultimately reduce thelife of the drill bit changing system.

For the drill bit changer to operate reliably it will need to beconstructed similar to the existing components of the drill rig system.The system which the drill bit changer was modeled after was the drillpipe changer. The drill pipe changing system uses a robust hydraulicallypowered system to add or subtract length to the in service drill pipe.The drill bit changing system will be similarly robust.

There are also quality and reliability objectives for the system. Thesystem must be structurally sufficient while holding multiple bits.Further, these bits must have a guaranteed alignment and position toensure system reliability.

The drill bit changing system will be able to withstand all of theincident stresses while in standby and drilling operation. Thesestresses can range from those caused by the weight of the bit to thosecaused by vibration during drilling.

Alignment is another consideration. To ensure reliability, the drill bitneeds to be in a guaranteed position to avoid cross threading a bit tothe drill pipe. A cross thread will cause an equipment shutdown becauseof an inability to remove the drill bit. To ensure alignment, the systemis constructed similar to the drill pipe exchanger, which uses positioncontrol via, for example, a slew drive.

The purpose of automating a system or process is to allow that processto run without any human interaction. To ensure a maximum of automationand a minimum of human interaction the changing system will need tohouse as many unused drill bits as possible.

Blast hole drill rigs operate in some very remote areas of the planet.These areas often times come with extreme conditions includingblizzards, earthquakes and hurricanes. Environmental conditions areworsened when dirt, dust and rock begin to be kicked up and thrownaround during drilling operation. To withstand these conditions, thesystem is structurally robust. As mentioned above, the system isdesigned based on existing drill rig components' structural robustnessto compensate for dangerous conditions.

Although the present embodiment(s) has been described in relation toparticular aspects thereof, many other variations and modifications andother uses will become apparent to those skilled in the art. It ispreferred therefore, that the present embodiment(s) be limited not bythe specific disclosure herein, but only by the appended claims.

What is claimed is:
 1. A drill bit changer system for a drill rig, thesystem comprising: a drill bit storage holder rotatably and pivotallymounted to the drill rig; and a plurality of bit holder assemblieslocated within the drill bit storage holder, each bit holder assemblyincluding a receptacle, wherein the plurality of bit holder assembliesare arranged to receive a drill bit in each receptacle, the drill bitstorage holder being pivotally connected between a stowed position andan engaged position in which the drill bit is positioned at a drillstring of the drill rig, wherein the drill bit storage holder is furtherindexable to present a respective receptacle at the drill string suchthat the drill bit is added or removed from the drill string.
 2. Thedrill bit changer system of claim 1, wherein the drill bit storageholder is a rotatable carousel.
 3. The drill bit changer assembly ofclaim 1, wherein the drill bit storage holder is indexable by a slewdrive.
 4. The drill bit changer system of claim 1, wherein the drill bitstorage holder is pivotally connected to a mast of the drill rig
 5. Thedrill bit changer system of claim 4, wherein the drill bit storageholder is pivotally connected to the mast by at least one hydraulicallyoperated arm.
 6. The drill bit changer system of claim 1, furthercomprising at least one processing device arranged to execute a computerexecutable code to control the pivotable and rotatable movement of thedrill bit storage holder.
 7. The drill bit changer system of claim 1,wherein each bit holder assembly has opposed ends, the receptacle beingpositioned at one end of the bit holder assembly and an adaptor armbeing positioned at the other end.
 8. The drill bit changer system ofclaim 7, further comprising a plurality of adaptor assemblies eachincluding an adaptor having opposed ends, one end of the adaptor beingarranged to engage the drill string of the drill rig and another end ofthe adaptor being engageable with the drill bit, wherein the adaptor hasa section disposed between the opposed ends, the section beingengageable by the adaptor arm disposed in the bit holder assembly toengage and disengage the drill bit adaptor assembly from the drillstring.
 9. The drill bit changer system of claim 1, wherein the drillbit storage holder has a top arranged to contain the bit holderassemblies and bits therein.
 10. The drill bit changer system of claim1, wherein the drill bit is cupped within the receptacle.
 11. A methodof changing a drill bit of a drill rig comprising the steps of:providing a drill bit changer system, the drill bit changer systemincluding a drill bit storage holder rotatably and pivotally mounted tothe drill rig, and a plurality of bit holder assemblies located withinthe drill bit storage holder, each bit holder assembly including areceptacle, wherein the plurality of bit holder assemblies are arrangedto receive a drill bit in each receptacle; pivoting the drill bitstorage holder to a first position whereby the drill bit storage holderis positioned to engage a drill string of the drill rig; removing a useddrill bit and adaptor assembly from the drill string; indexing the drillbit storage holder to position a new drill bit to the drill string;attaching the new drill bit adaptor assembly to the drill string; andpivoting the drill bit storage system to a second position whereby thedrill bit storage system is stowed away from the drill string.
 12. Themethod of claim 11, wherein the pivotal movement of the drill bitstorage system and the indexing of the drill bit storage holder iscontrolled by a computerized control unit executing a computerexecutable code.
 13. The method of claim 11, wherein the drill bitchanger system further comprises a plurality of adaptor assemblies eachincluding an adaptor having opposed ends, one end of the adaptor beingarranged to engage the drill string of the drill rig and another end ofthe adaptor being engageable with the drill bit, wherein the adaptor hasa section disposed between the opposed ends, the section beingengageable by an adaptor arm disposed in the bit holder assembly toengage and disengage the drill bit adaptor assembly from the drillstring.